High-Accurary Numerical and Experimental Analysis of Controlled Viscous Limit-Cycle Oscillations in a Micro Air Vehicle Model

Abstract

The present Final Year Project aims to study the aeroelastic behaviour of a 3D aircraft wing by FluidStructure Interaction. Aeroelasticity is a physical phenomenon resulting from the interaction of aerodynamic, elastic and inertial forces. Flutter, is an unstable self-excited vibration in which the structure extracts energy from the air stream and often results in catastrophic structural failure. These coupling occurs when the aerodynamic forces associated with motion in two modes of vibration cause the modes to couple in an unfavourable manner. ANSYS Fluid-Structure Interaction Framework, FSIF, was designed to discretise both fluid and structural domains. FSI Methods are validated with one way and two-way coupling methods. Reynolds Averaged Navier-Stokes equation and Turbulence Transport equations governing the flow were integrated in the FSI solver. The results are presented for an RV-10 wing structure denoted as reference case. K-P Method was defined to stablish critical flutter speed and flutter limits. Simulations were run for steady and transient models by applying SST K-omega turbulence model into ANSYS FSIF. Furthermore, numerical results have been post-processed in order to obtain the phase difference and classical coupling motion. Those results indicate unstable flow for the selected Critical Flutter Speed. Comparison between literature review on rectangular wings and numerical results shows accurate results. Moreover, experimental pressure distributions of an oscillating wing tested at European University Wind Tunnel facility are analysed aiming to provide accurate results. Despite the simplifications implemented in both the fluid and structural solvers, this framework proves to be useful to predict the aeroelastic performance of a wing in the early stages of aircraft design.